Microelectronic modules containing high power microelectronic devices, such as Radio Frequency (RF) semiconductor die, often generate excess heat during operation. For this reason, microelectronic modules are commonly fabricated to contain copper or other metal structures for purposes of enhanced heat dissipation. In certain cases, the metal structures may assume the form of metal structures, such as metal slugs or “coins,” embedded within a module substrate, such as a coreless substrate or a Printed Circuit Board (PCB). A metal coin may be embedded in a multilayer PCB in situ by building-up the PCB laminates around the metal coin. Alternatively, a metal structure may be created during production of a coreless substrate utilizing a sequential plating process. As a still further possibility, a metal coin may be installed post module substrate fabrication by, for example, pressing fitting the metal coin into an opening formed through the substrate by mechanical or laser drilling. While module substrates containing embedded metal coins can provide enhanced local heat dissipation, such substrates are often undesirably costly to manufacture, prone to substrate warpage (particularly in the case of coreless substrates), and associated with other shortcomings. More generally, even when produced utilizing embedded coin substrates, microelectronic modules may still experience undesirably high heat concentrations when operated at elevated power levels, such as power levels exceeding 1 watt and possibly approaching or exceeding 5 watts, as may be desirable in certain microwave and RF applications. Accordingly, there exists an ongoing demand for microelectronic modules having enhanced heat dissipation capabilities and which are amenable to fabrication utilizing efficient, cost effective, warpage-resistant manufacturing processes.
For simplicity and clarity of illustration, descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the exemplary and non-limiting embodiments of the invention described in the subsequent Detailed Description. It should further be understood that features or elements appearing in the accompanying figures are not necessarily drawn to scale unless otherwise stated. For example, the dimensions of certain elements or regions in the figures may be exaggerated relative to other elements or regions to improve understanding of embodiments of the invention.